Registration Dossier
Registration Dossier
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EC number: 243-818-5 | CAS number: 20429-33-8
Partition coefficient
Administrative data
Link to relevant study record(s)
- Endpoint:
- partition coefficient
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- April 25, 2017
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
- Version / remarks:
- 2004
- Deviations:
- no
- GLP compliance:
- yes
- Type of method:
- HPLC method
- Partition coefficient type:
- octanol-water
- Analytical method:
- high-performance liquid chromatography
- Key result
- Type:
- log Pow
- Partition coefficient:
- 6.86
- Temp.:
- 23 °C
- pH:
- 6
- Details on results:
- OBSERVATIONS
- A method development run under standard OECD 117 conditions (methanol:water (75:25)) did not yield a useful chromatogram as the test substance retained surfactant qualities and did not interact properly with the column. Increasing the methanol content to 90% negated the test substance’s surfactant qualities.
- It was determined that by running the test substance in a high methanolic mobile phase, methanol:water (90:10), a chromatogram could be obtained with two, well resolved main peaks. The calibration standards provided a useable calibration curve under these conditions.
- There were two main peaks found in the chromatogram, at 6.8 and 8.6 minutes. All other peaks were less than five percent of the total area.
RESULTS
- The test substance was composed of two main components with several minor components, displayed as many peaks, ranging in retention time from approximately 3 to 13 minutes. Only peaks with an area greater than five percent of the total were included in the calculations of Kow.
- The error in the measurements was estimated using the relative percent difference (RPD) of the two independent preparations analysed in these experiments. The difference between the two preparations was 0.009 log units, corresponding to 0.12% RPD for neutral pH.
- The test substance displayed a weight-averaged log Kow of 6.860 at neutral pH as per the method in OECD Test No. 117. - Conclusions:
- Under the study conditions, the test substance displayed a weight-averaged log Kow of 6.860 at neutral pH.
- Executive summary:
A study was conducted to determine the partition coefficient of the test substance according to OECD Guideline 117 using the HPLC method. The test substance did not retained well using a methanol:water 75:25 mobile phase but did retained well when after switching to a mobile phase with higher methanol content (90:10). The increased methanol content gave rise to sharper peaks that could be used for OECD 117 calculations. The calibration standards were also run in this mobile phase. Two individual preparations of the test substance standards were made. The test substance was composed of two main components with several minor components, displayed as many peaks, ranging in retention time from approximately 3 to 13 minutes. Only peaks with an area greater than five percent of the total were included in the calculations of Kow. The error in the measurements was estimated using the relative percent difference (RPD) of the two independent preparations analysed in these experiments. The difference between the two preparations was 0.009 log units, corresponding to 0.12% RPD for neutral pH. Under the study conditions, the test substance displayed a weight-averaged log Kow of 6.860 at neutral pH (Ford, 2017).
Reference
Table 1: Summary of Partition Coefficient Data in Neutral Conditions
Preparation Number |
Concentration (µg/mL) |
Peak Retention Time (min) |
Peak Area (%) |
log Kow |
Weighted Average logKow |
1 |
Test substance in MeOH:Water (90:10) |
6.846 |
26.34 |
6.14 |
6.865 |
8.671 |
57.06 |
7.20 |
|||
2 |
Test substance in MeOH:Water (90:10) |
6.841 |
25.91 |
6.14 |
6.856 |
8.641 |
56.81 |
7.18 |
|||
Average |
6.860 |
||||
Relative Percent Difference (RPD, %) |
0.12 |
||||
Absolute Difference (log units) |
0.009 |
||||
Description of key information
The partition coefficient was determined according to OECD Guideline 117 (Ford, 2017).
Key value for chemical safety assessment
- Log Kow (Log Pow):
- 6.86
- at the temperature of:
- 23 °C
Additional information
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
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